Engine systems may be configured with boosting devices, such as turbochargers or superchargers, for providing a boosted aircharge and improving peak power outputs. Responsive to the boosted output provided by such engine systems, efficient operation of a spark plug and stable combustion may be achieved by providing high peak secondary currents at high speed and high load conditions, while providing long spark durations at low speeds and loads under lean and/or dilute conditions. However, high peak secondary currents and long spark durations are competing characteristics for ignition coil configuration, resulting in systems that devalue operation under one or more of the above-identified conditions in favor of another condition.
The inventors have recognized the issues with the above approach and offer a system to at least partly address them. In one embodiment, a system comprises a first inductive ignition coil including a first primary winding and a first secondary winding and a second inductive ignition coil including a second primary winding and a second secondary winding. The second secondary winding is connected in series to the first secondary winding. The system further comprises a diode network including a first diode and a second diode connected between the first secondary winding and the second secondary winding.
In this way, each the two coils may be configured for a different one of the competing characteristics (e.g., high peak secondary currents or long spark duration), and steering diodes combine the output of each coil such that additional spark energy is only provided when operating conditions warrant.
The present disclosure may offer several advantages. For example, by only providing long spark duration when operating conditions call for additional spark energy, overall electrical energy consumption may be decreased in comparison to systems that always provide long spark duration. Further, the configuration decreases component stress, thereby extending component life span, by exposing the current steering diodes to a much lower maximum voltage in comparison to diodes utilized in parallel connected dual coil ignition systems. Furthermore, the lower maximum voltage enables compact coil packaging of a plug top coil positioned on top of a pencil or stick coil, thereby decreasing packaging real estate requirements on the engine in comparison to dual coil systems that are constructed with two side by side plug top coils in one housing or two separate coil packages.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.